Rechargeable batteries have been used for electrical energy storage in a wide range of applications including their use in vehicles, power tools, lap-top computers, mobile phones, two-way radios, lights, and uninterruptible power supplies. Vehicles that use rechargeable batteries include automobiles, boats, and aircraft that have batteries for starting the vehicle, electric vehicles including golf carts, and hybrid electric vehicles. Hybrid electric vehicles typically have both batteries and another source of power, such as an internal combustion engine and a generator, a fuel cell, or photovoltaics.
Electric chargers and methods of charging have been developed and used for charging batteries, including batteries in electric vehicles. Chargers have been used in stationary applications, and have also been installed on vehicles to charge batteries located on the vehicles. Stationary chargers that use power from the electric power grid have also been widely used. Chargers located on vehicles may also be configured to plug into the electric power grid, or may obtain power from an on-board source of power, such as an internal combustion engine, or from a motor/generator used for regenerative braking as the vehicle decelerates.
In the case of stationary applications, chargers have typically been designed to charge one particular type of battery. However, batteries are currently being used of various types, each typically requiring its own voltage, current, and the like for optimal charging. Chargers have been invented that can charge more than one type of battery, wherein the user can manually select the type of battery to be charged. However, this requires a user to select the correct type of battery, and there is a risk that the user may inadvertently select the wrong type. This could result in a failure to charge the battery and could damage either the battery or the charger. Thus, a need exists for a charger that can automatically identify the type of battery that it is connected to and charge the battery in a safe, efficient, and convenient manner.
In addition, in the past, chargers have typically been relatively slow. Many chargers have been designed to charge a battery slowly to avoid charging it too quickly or overcharging it. But in many applications, this results in the battery, or electric vehicle, for example, being out of operation for a long time while it is being charged. In many applications, a need exists for a charger that can charge a battery at or near the optimum or maximum rate at which the battery can be safely charged. Also, a need exists for a method for charging batteries that can be used reliably to charge batteries at or near the optimal or maximum rate. In the specific application of electric vehicles, a need exists for a charger that will quickly charge an electric vehicle while the operator waits, similar in experience to fueling a fossil-fuel powered vehicle.
Furthermore, in the past, many chargers have been bulky and heavy, and a need exists to reduce their size, mass, or both. For instance, chargers have been developed that use alternating current, and transform the alternating current from one voltage to another using one or more wire-wound transformers. The transformer or transformers typically form a substantial portion of the size and mass of such chargers. Large transformers for 60-cycle operation were typically used. Thus, a need exists to reduce the size and mass of chargers, and specifically the size and mass of transformers used in chargers. This need exists for stationary transformers, but may be even more important in vehicles where the charger must be carried around on board the vehicle.
Even further, a need exists for battery chargers, including electrical vehicle chargers, and methods of charging batteries, that fulfill a plurality or all of these needs, are capable of quickly charging most types of batteries used in the particular application, are easy and safe to use, and inexpensive to manufacture and maintain. Other needs exist that are apparent from this document.